PROGNOSTIC SCORING IN ADULT ASTROCYTIC TUMORS USING PATIENT AGE, HISTOPATHOLOGICAL GRADE, AND DNA HISTOGRAM TYPE

High-grade astrocytic tumors constitute the most serious as well as th e most common group of primary brain tumors. Although several prognost ic factors have been proposed, little is known about the prognostic va lue of deoxyribonucleic acid (DNA) ploidy in adult astrocytic tumors. In a series of 146 adult patients, aged 16 to 82 years, the individual prognostic values of six variables were studied, namely: tumor histop athological grade, treatment, patient age, extent of tumor, ploidy lev el, and DNA histogram type. Cox's proportional hazard model was then a pplied to the data to ascertain which factors might independently dete rmine patient survival. Univariate analyses revealed that histopatholo gical grade, age, and DNA histogram type were very powerful prognostic factors. The statistical significance of the influence of adjuvant ra diotherapy and chemotherapy was at a borderline level, and the two rem aining variables (tumor extent and ploidy level) had no prognostic rel evance. Multivariate analyses showed that age, histopathological grade , and DNA histogram type were independent, statistically significant p rognostic factors. A prognostic score was calculated from Cox's polyno mial function in which those factors were introduced. The best score c orresponded to a patient aged 16 years with a hypertriploid low-grade astrocytoma, while the worst score corresponded to a patient aged 82 y ears with a diploid high-grade astrocytoma. The worst score:best score ratio revealed a risk 71 times higher for a bad prognosis. It is conc luded that patient age, histopathological grade, and DNA histogram typ e are very powerful prognostic factors for adult astrocytic tumors. A prognostic score including those factors could be used to characterize astrocytic tumor aggressiveness presurgically on fine-needle aspirate s, and to monitor the patient's postsurgical evolution to define the a ppropriate therapy.